Complexes of Block Ionomers With Oppositely Charged Surfactants

该项目的主要目标是探索两种类型的环境响应型纳米复合材料。第一种材料通过使含有离子和非离子链段的嵌段（或接枝）共聚物与带相反电荷的表面活性剂反应来合成。第二种材料通过使含有离子和非离子链段的交联网络与带相反电荷的表面活性剂反应来合成。最终的材料结合了联合收割机两个主要元素。首先，它们含有离子聚合物链段，其被带相反电荷的表面活性剂离子中和以形成水不溶性域。第二，它们含有与离子链连接的非离子聚合物链段，其提供整个复合物在适当溶剂中的分散或溶胀。 对于这些嵌段离聚物复合物（BIC），PI将表征组分的结构参数与所得BIC的物理化学性质之间的关系，并检查此类系统中结构形成的控制途径和程度。为此目的，共聚物的分子结构（即线性与支化、嵌段与接枝、链段长度等）以及表面活性剂的结构（即，氢尾对碳氟化合物尾、尾的数量和它们的长度）将变化。将检查这些材料对pH值、离子强度、溶剂和温度变化的响应。该项目的第二部分将使用离子和非离子亲水性聚（环氧乙烷）（PEO）链的交联聚合物网络来扩展BIC家族。预计在与带相反电荷的表面活性剂反应后，将形成部分溶胀的微非均质本体材料，其中来自聚离子结合的表面活性剂阵列的疏水簇通过亲水性PEO链连接。疏水簇的大小和结构以及溶胀的亲水区，它们的渗透和溶胀程度应强烈依赖于整体复合物组合物以及原始嵌段离聚物网络的特性。这种敏感性可能是有效控制BIC网络特性的关键，从而使其能够用作环境响应材料。这些研究将促进对设计具有可控性质的聚合物-表面活性剂分散体和网络所涉及的原理的理解。 来自聚合物网络和表面活性剂的复合物可用作多种应用中的通用环境响应性材料，包括用于生物分离、生物催化、药物递送和药物释放系统的树脂。因此，如果这项研究成功，它可能会在需要纳米复合材料的各个领域产生更广泛的影响。

The major goal of this project is to explore two types of environmentally responsive nanocomposite materials. The first materials are synthesized by reacting block (or graft) copolymers, containing ionic and nonionic segments, with oppositely charged surfactants. The second materials are synthesized by reacting cross-linked networks containing ionic and nonionic segments, with oppositely charged surfactants. The resulting materials combine two major elements. First, they contain ionic polymer segments, which are neutralized with oppositely charged surfactant ions to form water insoluble domains. Second, they contain nonionic polymer segments linked to ionic chains, which provide for dispersion or swelling of a whole composite in appropriate solvents. For these block ionomer complexes (BIC), the PI will characterize the relationships between the structural parameters of the components and physicochemical properties of the resulting BIC, as well as examines the routes and extent of control of structure formation in such systems. For this purpose the molecular architecture of the copolymers (i.e. linear vs. branched, block vs. graft, length of the segment etc.) as well as the structure of surfactants (i.e., hydro- vs. fluorocarbon tails, number of tails and their lengths) will be varied. The response of these materials to pH, ionic strength, solvents and temperature variations will be examined. The second part of this project will extend the family of BIC using cross-linked polymer networks from ionic and nonionic hydrophilic poly(ethylene oxide) (PEO) chains. It is expected that upon reacting with oppositely charged surfactants, a partially swollen microheterogeneous bulk material will form in which the hydrophobic clusters, from polyion-bound surfactant arrays, are joined by hydrophilic PEO chains. The size and the structure of hydrophobic clusters as well as swollen hydrophilic zones, their percolation and degree of swelling should be strongly dependent on the overall complex composition as well as the characteristics of the original block ionomer network. It is possible that such sensitivity will be a key to effective control of the properties of BIC networks allowing their use as environmentally responsive materials. These studies will advance the understanding of the principles involved in designing polymer-surfactant dispersions and networks with controllable properties. Complexes from polymer networks and surfactants might be useful as versatile environmentally responsive materials in a variety of applications, including resins for bioseparation, biocatalysis, drug delivery and drug release systems. Therefore, if this research is successful, it might have broader impact in various fields where nanocomposite materials are needed.